In my opinion chatsecure (guardian repo via f-droid, 14.2.3) works great. Unfortunately ZOM (188.8.131.525) not yet.
Attempt to start encryption takes too long, often with no success (in two directions).
The same problem is with verification by question.
Would be nice to have a mobile client for android that supports omemo and activates it by default so I can recommend it to non-nerds. Unfortunately Conversations is not an option (try telling people to choose between different cyphers for every user 😞 ).
Zom iOS now has the OMEMO code integrated. We plan to release it by early April with OMEMO enabled. We are simultaneously working on integrated Smack-OMEMO project in Zom Android, as well, with at least a public beta in April.
Yes, absolutely. We are just finishing up a major update of our groupchat user interface and reliability now (15.3 now in beta!). Our next sprint in early October is OMEMO MUC. Got some cycles to contribute?